An FMS may be out of currency (or lack of it) provided:
1- Current aeronautical charts are used to verify navigation fixes prior to dispatch.
2- Procedures are established and used to verify status and suitability of navigation facilities used to define route of flight.
3- Navigation radios are manually tuned and identified.
4- Step-by-step insertion and/or verification of waypoint coordinates based on aeronautical charts and flight plan.
5- Revision of dep/arr procedures and legs pages with current dep/app charts. In case of disagreement use manual/raw data based on the "old" ground navigation infrastructure as the primary and solely mean of navigation (back to basics).